FDA Warns of Potential Pulse Oximeter Inaccuracies Feb. 22, 2021 -- Pulse oximeters, which measure blood oxygen levels, have become popular during the COVID-19 pandemic for people to track their oxygen saturation, but they may not always be accurate, the FDA cautioned in new guidance released Friday. Several factors can affect the accuracy of pulse oximeters, including poor circulation, skin temperature, skin thickness, current tobacco use, use of fingernail polish, and dark skin pigmentation, the FDA said. Recent reports have found that Black patients may not receive accurate readings from some oximeters. “While pulse oximeters may be useful for estimating blood oxygen levels, these devices have limitations that can result in inaccurate readings,” William Maisel, MD, director of the FDA’s Office of Product Evaluation and Quality, said in a statement.